uart, ioports, etc. Many more changes

[simavr] / simavr / sim / sim_interrupts.c

diff --git a/simavr/sim/sim_interrupts.c b/simavr/sim/sim_interrupts.c
new file mode 100644 (file)
index 0000000..545123e
--- /dev/null
+++ b/simavr/sim/sim_interrupts.c
@@ -0,0 +1,120 @@
+/*
+       sim_interrupts.c
+
+       Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
+
+       This file is part of simavr.
+
+       simavr is free software: you can redistribute it and/or modify
+       it under the terms of the GNU General Public License as published by
+       the Free Software Foundation, either version 3 of the License, or
+       (at your option) any later version.
+
+       simavr is distributed in the hope that it will be useful,
+       but WITHOUT ANY WARRANTY; without even the implied warranty of
+       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+       GNU General Public License for more details.
+
+       You should have received a copy of the GNU General Public License
+       along with simavr.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "sim_interrupts.h"
+#include "sim_core.h"
+
+void avr_register_vector(avr_t *avr, avr_int_vector_t * vector)
+{
+       if (vector->vector)
+               avr->vector[vector->vector] = vector;
+}
+
+int avr_has_pending_interrupts(avr_t * avr)
+{
+       return avr->pending[0] || avr->pending[1];
+}
+
+int avr_is_interrupt_pending(avr_t * avr, avr_int_vector_t * vector)
+{
+       return avr->pending[vector->vector >> 5] & (1 << (vector->vector & 0x1f));
+}
+
+int avr_raise_interrupt(avr_t * avr, avr_int_vector_t * vector)
+{
+       if (!vector || !vector->vector)
+               return 0;
+//     printf("%s raising %d\n", __FUNCTION__, vector->vector);
+       // always mark the 'raised' flag to one, even if the interuot is disabled
+       // this allow "pooling" for the "raised" flag, like for non-interrupt
+       // driven UART and so so. These flags are often "write one to clear"
+       if (vector->raised.reg)
+               avr_regbit_set(avr, vector->raised);
+       if (vector->enable.reg) {
+               if (!avr_regbit_get(avr, vector->enable))
+                       return 0;
+       }
+       if (!avr_is_interrupt_pending(avr, vector)) {
+               if (!avr->pending_wait)
+                       avr->pending_wait = 2;          // latency on interrupts ??
+               avr->pending[vector->vector >> 5] |= (1 << (vector->vector & 0x1f));
+
+               if (avr->state != cpu_Running) {
+               //      printf("Waking CPU due to interrupt\n");
+                       avr->state = cpu_Running;       // in case we were sleeping
+               }
+       }
+       // return 'raised' even if it was already pending
+       return 1;
+}
+
+void avr_clear_interrupt(avr_t * avr, int v)
+{
+       avr_int_vector_t * vector = avr->vector[v];
+       avr->pending[v >> 5] &= ~(1 << (v & 0x1f));
+       if (!vector)
+               return;
+       printf("%s cleared %d\n", __FUNCTION__, vector->vector);
+       if (vector->raised.reg)
+               avr_regbit_clear(avr, vector->raised);
+}
+
+/*
+ * check wether interrupts are pending. I so, check if the interrupt "latency" is reached,
+ * and if so triggers the handlers and jump to the vector.
+ */
+void avr_service_interrupts(avr_t * avr)
+{
+       if (!avr->sreg[S_I])
+               return;
+
+       if (avr_has_pending_interrupts(avr)) {
+               if (avr->pending_wait) {
+                       avr->pending_wait--;
+                       if (avr->pending_wait == 0) {
+                               int done = 0;
+                               for (int bi = 0; bi < 2 && !done; bi++) if (avr->pending[bi]) {
+                                       for (int ii = 0; ii < 32 && !done; ii++)
+                                               if (avr->pending[bi] & (1 << ii)) {
+
+                                                       int v = (bi * 32) + ii; // vector
+
+                                               //      printf("%s calling %d\n", __FUNCTION__, v);
+                                                       _avr_push16(avr, avr->pc >> 1);
+                                                       avr->sreg[S_I] = 0;
+                                                       avr->pc = v * avr->vector_size;
+
+                                                       avr_clear_interrupt(avr, v);
+                                                       done++;
+                                                       break;
+                                               }
+                                       break;
+                               }
+                       }
+               } else
+                       avr->pending_wait = 2;  // for next one...
+       }
+}
+